Th(IV) adsorption on mesoporous molecular sieves: effects of contact time,solid content,pH, ionic strength,foreign ions and temperature

The mesoporous molecular sieves (Al-MCM-41) are synthesized with montmorillonite as silica–alumina source by hydrothermal method. The application of Al-MCM-41 for the adsorption of Th(IV) from aqueous solution is studied by batch technique. The effects of contact time, solid content, pH, ionic strength, foreign ions, and temperature are determined, and the results indicate that the adsorption of Th(IV) to Al-MCM-41 is strongly dependent on pH values but independent of ionic strength. The adsorption isotherms are simulated by D–R and Freundlich models well. The thermodynamic parameters (ΔH ⁰, ΔS ⁰, ΔG ⁰) are calculated from the temperature dependent adsorption isotherms at 293, 313 and 333 K, respectively, and the results suggest that the adsorption of Th(IV) on Al-MCM-41 is a spontaneous and endothermic process. Al-MCM-41 is a suitable material for the preconcentration of Th(IV) from large volumes of aqueous solutions.